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J. Anat. (1999) 195, pp. 551–562, with 1 figure Printed in the United Kingdom 551

Scoring of nonmetric cranial traits : a population study

P. BRASILI, L. ZACCAGNI AND E. GUALDI-RUSSO

Dipartimento di Biologia Evoluzionistica Sperimentale, Area di Antropologia Universita[ degli Studi di Bologna, Bologna,

Italy

(Accepted 22 June 1999)

The aims of the present study were: (1) to supply further knowledge about variations in nonmetric cranial

traits in relation to sex, age and laterality and (2) to evaluate biological distance between samples from a

recent population. The incidence of 18 nonmetric variants of the cranium were determined in 3 adult

samples of 394 skulls of known sex from North Sardinia (Sassari, Alghero and Ozieri) ; for the Sassari

sample (n¯ 200) age at death was also known. Some significant sex differences were observed. Age did not

appear to influence the frequency of the discontinuous traits but did for legibility. Side differences may

provide important information about environmental influences. The interpopulation analysis indicates a

stronger relationship between samples that are geographically closer (Sassari and Alghero), in accordance

with other studies, strengthening the hypothesis of the validity of the use of nonmetric traits in the study of

the peopling of a territory.

Key words : Osteology; skull ; discontinuous traits ; biological distance.

Discontinuous traits of the skull have been widely

used since the early 1900s as tools for the evaluation

of the genetic variability of human populations, for

assessment of the existence of parental structures

within a community, or as taxonomic indicators. They

are among the traits that permit measurement of the

biological distances between past populations. Ac-

cording to Buikstra et al. (1990), this type of study

represents ‘an important component of contemporary

physical anthropological investigation’. Their use can

enable the provision of answers to evolutionary or

microevolutionary questions and investigation of

archeological problems such as models of settling and

cultural stability, as well as paleodemographic and

paleopathological topics.

The employment of discontinuous traits in anthro-

pology has certainly been spurred by their apparent

ease of scoring and the fact that they are believed to

be genetically determined, even though partly under

environmental control. The multiplication of studies,

however, has highlighted various problems in the use

of nonmetric traits in human population studies.

Correspondence to Prof. P. Brasili, Dipartimento di Biologia Evoluzionistica Sperimentale, Area Antropologica, Universita' degli Studi di

Bologna, Via Selmi n.3, 40126 Bologna, Italy. Tel. : 39 051 209193; fax: 39 051 209191; e-mail : brasili!alma.unibo.it

These relate to their choice, the existence of an

effective genetic basis and the effects of the en-

vironment on their expression. In addition, from a

methodological standpoint there is a lack of agree-

ment between various authors on the importance of

sex differences in these investigations. Many re-

searchers believe that the sexes must be kept separate

in the analysis of discontinuous traits (Woo, 1950;

Berry, 1975; Ossenberg, 1976; Muller, 1977; Benassi-

Graffi et al. 1979a, b ; Brasili-Gualandi & Gualdi-

Russo, 1980, 1981, 1989; Goldstein et al. 1980;

Turbon & Pons, 1982; Cesnys, 1982; Dahinten &

Pucciarelli, 1983; Milne et al. 1983; Axellson &

Hedegaard, 1985) while others maintain that this

factor of variability has little importance (Vecchi,

1968; Reggio et al. 1969; Cosseddu et al. 1979;

Scarsini et al. 1980; Prowse & Lovell, 1995). Still

others prefer to exclude traits that exhibit sex

differences (Perizonius, 1979; Conner, 1990; Konigs-

berg, 1990). A similar situation exists with respect to

age. Indeed, for some traits, e.g. the foramina, it

would perhaps be preferable to exclude elderly

subjects. Another widely debated problem is whether

possible asymmetries of expression of bilateral traits

should be considered (Conner, 1990; Konigsberg

1990; Pathak & Kaul, 1991; Christensen, 1997).

Despite being widely discussed in the literature, these

problems have not received complete and satisfactory

answers.

The present study falls within the context of this

debate. Its first aim was to analyse the importance of

sex, age and laterality in human population studies

based on nonmetric traits, while the second was to

evaluate the biological differentiation of some pop-

ulations of northern Sardinia (Sassari, Alghero,

Ozieri) through the calculation of biological distance.

We examined the skulls of Sardinian adults, of known

sex, exhumed in the early 1900s. In particular, 3

samples were analysed: 1 from Sassari (100 M, 100 F),

for which the age at death was also known, and the

other 2 from Alghero (65 M, 32 F) and Ozieri (62 M,

35 F). The material is contained in the Frassetto

Collection of the Department of Experimental Evol-

utionary Biology—Anthropology Unit, University of

Bologna, Italy. We scored 18 nonmetric traits ac-

cording to the modalities reported in the preceding

paper aimed at assessing the intra and interobserver

(Gualdi-Russo et al. 1999). In the scoring, we took

into account the points that emerged from that study,

i.e. the importance both of the researcher’s experience

and of a definition of the traits that leaves no room for

misinterpretation. The scorings were therefore carried

out by experts after mutual standardisation of the

scoring methods.

The following indications were also followed:

individuals older than 70 y were excluded, the sexes

were analysed separately, and both sides were scored

for bilateral traits.

For the sample of Sassari (the largest one), we

evaluated the possible differences between the sexes

and the correspondence between sides in the ex-

pression of the trait. The homogeneity of the

distribution of traits between sexes was assessed by

the χ# test. The difference between sides was assessed

by the formula χ#

!¯ (b®c)#}(bc) (Green et al.

1979), where b is left presence-right absence and c is

right presence-left absence, which is distributed as for

χ# with 1 .. The correlation between sides was

evaluated by the formula

φ¯²(ad®bc)#}(ab) (ac) (bd) (cd)´"#

where a is bilateral presence, b is left presence only, c

is right presence only, d is bilateral absence (Green

et al. 1979).

Since the age at death of the subjects in the Sassari

sample was known, it was possible to assess the

relation between this factor of variability and the trait

frequencies. To this purpose, the sample was divided

into 3 classes : ! 40 y (33 M, 33 F), 40–60 y (37 M,

37 F) and " 60 y (30 M, 30 F). The comparison was

made by χ#.

The biological distances between subsamples of

Sardinian population were calculated by MMD (mean

measure of divergence). The MMD between samples

1 and 2 is then given by the formula (Sjøvold, 1977;

Green et al. 1979) :

MMD¯ 1}r3j=",r

(θ"j®θ

#j)#®V

"#j

where: r¯number of traits considered, θ¯ "

#arcsin

(1®2x}(n1))"

#arcsin (1®2(x1)}(n1)), x¯

number of times the trait occurs, n¯number of sides

available for observation, and V"#j

is a correction

term. In particular :

V"#j

¯ (1}(N #

"j}(N

"j2n

"jφ"j)0±5))

(1}(N #

#j}(N

#j2n

#jφ#j)0±5))

for bilateral traits and

V"#j

¯ 1}(n"j0±5)1}(n

#j0±5)

for unilateral traits, where Nij¯ total number of sides

examined for jth trait in population i, nij¯number of

crania intact on both sides examined for jth trait in

population i, φij¯ the estimated correlation in the

occurrence of the jth trait from side to side in

population i found using the formula of Green et al.

(1979) previously reported.

In order to test the MMD values for significance,

the following formula was computed:

SDMMD

¯oVarMMD

¯o2}r# 3j=",r

V #

"#j.

If MMD}SDMMD

" 2, then the compared samples are

regarded as significantly divergent.

These distances were represented by means of

UPGMA (Numerical Taxonomy and Multivariate

Analysis¯NTSYS-pc; Rohlf, 1992). In the calcu-

lation of biodistance, the correlation between traits

was not considered. Although some authors (Conner,

1990; Konigsberg, 1990; Sciulli, 1990) have attributed

some importance to this element in the calculation of

biological distance, the data reported in the literature

are rather discordant, with associations that are

difficult to interpret and sometimes attributable to

sampling. Prowse & Lovell (1995) have underlined

that the correlation between traits in the various

studies has rarely reached statistical significance in

small samples.

552 P. Brasili, L. Zaccagni and E. Gualdi-Russo

Analysis of the data was performed with the BMDP

programs (Dixon, 1988).

Intrapopulation analysis

As already stated, the first phase of the study was

aimed at broadening our knowledge of the variability

of discontinuous traits according to sex, age and

laterality.

The frequency of the discontinuous traits in the

Sassari sample shows that in both sexes (Table 1) the

Table 1. Presence of the discontinuous traits in Sessari male and female samples (D.F.¯ 1)

Males Females

Traits }n % }n % χ# P

1. Bregmatic bone 2}94 2±1 0.96 0 0±527 0±468

2. Coronal ossicle 10}88 11±4 10}90 11±1 0±003 0±958

3. Sagittal ossicle 4}58 6±9 2}83 2±4 1±687 0±194

4. Lambdoid ossicle 50}85 58±8 51}92 55±4 0±207 0±649

5. Ossicle at lambda 11}83 13±3 11}85 12±9 0±004 0±952

6. Ossicle at asterion 24}99 24±2 12}100 12±0 5±032 0±025*

7. Epipteric bone 17}86 19±8 24}97 24±7 0±649 0±421

8. Squamous ossicle 8}95 8±4 11}100 11±0 0±368 0±544

9. Parietal notch bone 31}99 31±3 25}100 25±0 0±981 0±322

10. Frontotemporal articulation 2}83 2±4 0}91 0 0±604 0±437

11. Parietal foramen absent 54}99 54±5 46}99 46±5 1±293 0±256

12. Auditory torus 3}100 3±0 0}100 0 3±046 0±081

13. Palatine torus 32}98 32±7 41}98 41±8 1±768 0±184

14. Maxillary torus 10}62 16±1 10}42 23±8 0±951 0±330

15. Foramen spinosum open 4}100 4±0 2}99 2±0 0±667 0±414

16. Supraorbital foramen complete 14}100 14±0 19}100 19±0 0±907 0±341

17. Inca bone 2}100 2±0 1}100 1±0 0±338 0±561

18. Metopism 12}100 12±0 4}100 4±0 2±661 0±103

*P! 0±05.

Table 2. Differences by sex in data from literature

Traits

Population Period n Reference 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

British (London) Recent 182 3 M ¯ } M ¯ M F } M ¯ } } F F F F } F

Dutch (Amsterdam) Recent 254 21 M F } ¯ ¯ ¯ F } F F } ¯ F ¯ F ¯ } M

Italians (Romans) Modern 300 16 M M } F M M M F ¯ ¯ } ¯ M ¯ ¯ M } ¯Caucasians Modern 139 33 ¯ ¯ F } F M F F F F } ¯ F F F } } F

American Indians ? 286 34 ¯ ¯ } M F M F } M F } M F } ¯ M M F

Ukrainians Prehistoric 169 36 ¯ M M M M M M F F F } M F } F M F M

Iroquois Historic 839 37 } } } M } } ¯ } M } } } } } F F } }Italians (Sardinia) ? 260 18 M M M F ¯ } F M M F } M ¯ ¯ } } } F

Sardinians (Sassari) Recent 200 Present

study

M ¯ M M ¯ M F F M F M M F F M F ¯ M

Sardinians (Alghero) Recent 96 Present

study

¯ ¯ M ¯ ¯ M F F F F F ¯ F ¯ ¯ ¯ ¯ ¯

Sardinians (Ozieri) Recent 96 Present

study

¯ F M M M M F M ¯ ¯ F ¯ M ¯ ¯ ¯ ¯ M

} Trait not considered; ¯, no difference ; F, higher frequency in females ; M, higher frequency in males.

most common traits are the lambdoid ossicle, parietal

foramen absent, palatine torus and parietal notch

bone. There is also almost complete overlap of the

sexes for the frequency of the coronal ossicle and

ossicle at lambda. The only significant difference is for

the ossicle at the asterion, which is more frequent in

males (P¯ 0±03), as reported previously for other

populations (Brasili-Gualandi & Gualdi-Russo, 1989;

Vecchi, 1968). A significantly higher frequency of

ossicle at asterion in males has also been reported in

recent Sardinians from Seui-Seulo (30 oss., P¯ 5%)

(Maxia et al. 1974). One of our previous studies

Population study of nonmetric traits 553

Table 3. Presence of the discontinuous traits by age in Sassari males (D.F.¯ 2)

Traits

! 40

(n¯ 33)

40–60

(n¯ 37)

" 60

(n¯ 30) n χ# P

Bregmatic bone 0}32 2}34 0}28 94 3±606 0±165

Coronal ossicle 5}31 4}32 1}24 88 1±952 0±377

Sagittal ossicle 3}27 1}21 0}10 58 1±637 0±441

Lambdoid ossicle 19}31 17}30 14}24 85 0±138 0±933

Ossicle at lambda 3}31 4}32 4}20 83 1±152 0±562

Ossicle at asterion 5}33 8}36 11}30 99 4±087 0±130

Epipteric bone 4}31 4}35 9}20 86 10±484** 0±005**

Squamous ossicle 2}33 1}35 5}27 95 5±213 0±074

Parietal notch bone 9}33 14}37 8}29 99 1±17 0±557

Frontotemporal articulation 1}30 0}35 1}18 83 1±731 0±421

Parietal foramen absent 19}33 19}37 16}29 99 0±279 0±870

Auditory torus 1}33 1}37 1}30 100 0±023 0±989

Palatine torus 11}33 14}37 7}28 98 1±205 0±547

Maxillary torus 6}26 4}24 0}12 62 3±241 0±198

Foramen spinosum open 2}33 1}37 1}30 100 0±562 0±755

Supraorbital foramen complete 7}33 6}37 1}30 100 4±412 0±110

Inca bone 2}33 0}37 0}30 100 4±143 0±126

Metopism 2}33 4}37 1}30 100 1±490 0±475

**P! 0±01.

Table 4. Presence of the discontinuous traits by age in Sassari females (D.F.¯ 2)

Traits

! 40

(n¯ 33)

40–60

(n¯ 37)

" 60

(n¯ 30) n χ# P

Bregmatic bone 0}33 0}35 0}28 96 — —

Coronal ossicle 4}32 2}35 4}23 90 2±013 0±366

Sagittal ossicle 0}33 1}30 1}20 83 1±494 0±474

Lambdoid ossicle 19}33 19}34 13}25 92 0±183 0±912

Ossicle at lambda 8}32 2}32 1}21 85 6±649 0±036*

Ossicle at asterion 5}33 5}37 2}30 100 1±199 0±549

Epipteric bone 12}33 7}35 5}29 97 3±692 0±158

Squamous ossicle 2}33 5}37 4}30 100 1±228 0±541

Parietal notch bone 9}33 7}37 9}30 100 1±221 0±543

Frontotemporal articulation 0}33 0}32 0}26 91 — —

Parietal foramen absent 16}33 18}36 12}30 99 0±739 0±691

Auditory torus 0}33 0}37 0}30 100 — —

Palatine torus 17}33 12}36 12}29 98 2±343 0±310

Maxillary torus 4}27 4}12 2}3 42 4±842 0±089

Foramen spinosum open 1}32 1}37 0}30 99 0±903 0±637

Supraorbital foramen complete 7}33 8}37 4}30 100 0±896 0±639

Inca bone 0}33 0}37 1}30 100 2±357 0±308

Metopism 1}33 1}37 0}30 100 0±884 0±643

*P! 0±05.

(Brasili-Gualandi & Gualdi-Russo, 1989) of sex as a

factor of variability in the expression of discontinuous

traits concluded that it was preferable to separate the

sexes in the collection and analysis of the data. Sciulli

(1990) found the ossicle at asterion, as well as

other traits not considered here, to be significantly

correlated with sex and excluded them from the

calculation of biodistance. Conner (1990) and

Konigsberg (1990) did the same, although they did

not specify the traits involved. However, from what is

reported in the literature (Table 2), it is evident that

the trend in the expression of these traits in relation to

sex is rather variable in different populations.

This aspect agrees with what has been observed

previously (Corruccini, 1974; Brasili-Gualandi &

Gualdi-Russo, 1989) and confirms the opinion that

the different responses to this source of variability in

the expression of discontinuous traits in human


Table 5. Comparison by side in males from Sassari†

Traits

d

®®c

®b

®a

n

χ#

(d.f.¯ 1) χ#

!φ

Coronal ossicle 74 3 4 3 84 9±399 0±14 0±418

88±1 3±6 4±8 3±6 0±002**

Lambdoid ossicle 35 8 8 32 83 31±286 0 0±614

42±2 9±6 9±6 38±6 0±0001**

Ossicle at asterion 75 12 6 6 99 9±293 2 0±306

75±8 12±1 6±1 6±1 0±0023**

Epipteric bone 65 0 9 6 80 28±108 9 0±593

81±3 — 11±3 7±5 0±0001** **

Squamous ossicle 84 3 0 5 92 44±022 3 0±777

91±3 3±3 — 5±4 0±0001**

Parietal notch bone 64 16 9 4 93 0±768 1±96 0±091

68±8 17±2 9±7 4±3 0±3807

Frontotemporal articulation 74 1 0 0 75 — 1 —

98±7 1±3 — —

Parietal foramen absent 45 11 20 23 99 12±357 2±61 0±353

45±5 11±1 20±2 23±2 0±0004**

Auditory torus 96 0 2 1 99 7±384 2 0±571

97 — 2 1 0±0059**

Palatine torus 66 4 5 23 98 58±529 0±11 0±773

67±3 4±1 5±1 23±5 0±0001**

Maxillary torus 42 0 2 5 49 26±068 2 0±826

85±7 — 4±1 10±2 0±0001**

Foramen spinosum open 93 2 2 0 97 5±321 0 0±021

95±9 2±1 2±1 — 0±0211*

Supraorbital foramen complete 86 5 6 3 100 5±256 0±09 0±294

86 5 6 3 0±0219*

† Percentage frequency and probability in italics ; *P! 0±05; **P! 0±01.

populations limit the possibility of assuming a precise

position on the subject. This induces us, in order to

limit the possible loss of information, to keep the sexes

separate whenever it is possible to diagnose the sex of

the skeletons.

In the Sassari sample, we also evaluated the possible

effect of age on the expression of the characters. In

general, the considered traits do not seem to be

influenced by age. In males (Table 3), only the

epipteric bone is significantly more frequent in the

oldest age group (" 60 y) (P¯ 0±005). In females

(Table 4), the ossicle at lambda is significantly

(P¯ 0±036) more frequent in the ! 40 y age group.

Nevertheless, it is difficult to believe that the differ-

ences observed in these traits can really be attributed

to the age of the individuals ; it seems more probable

that they are related to sampling. Finally, it should be

remembered that, as observed for sex, the results

obtained from various samples of a population can be

different, as also emphasised by Corruccini (1974) and

Sjøvold (1984).

We also ascertained whether there are differences in

the symmetric expression of the traits. Both in males

(Table 5) and females (Table 6), the symmetric

modality (a, d) is most frequent. The values of χ# are

statistically significant (P! 0±05) for practically all

traits, indicating a strong tendency to the same

expression of the nonmetric traits on both sides. The

exception in both sexes is the parietal notch bone and

in females only, the ossicle at asterion and supraorbital

foramen complete. However, the r values are generally

not very high; in fact, only in a few cases do they

approach 1 (Tables 5, 6). Considering the asymmetric

modality, we found that only the epipteric bone in

males has a significantly higher frequency on the right

side (χ#

!¯ 9; P! 0±005). A similar result was obtained

by Hauser & Bergman (1984) for the 2 medieval series

of Pitten and Zwentendorf combined (χ#

!¯ 4,9;

P! 0±05). In a sample from Siena previously studied

by us (Brasili-Gualandi & Gualdi-Russo, 1989), this

condition was observed for the lambdoid ossicle and

nasal foramen absent in males and females, for the

extrasutural ethmoidal foramen, supraorbital for-

amen complete and bipartite hypoglossal canal in

males and for the accessory infraorbital foramen and

frontal notch or foramen in females.

In general, the traits tend to exhibit a similar

expression on the 2 sides, as has been found in other

studies (Benassi-Graffi et al. 1979a, b ; Cosseddu et al.

1979; Korey, 1980; Ossenberg, 1981; McGrath et al.


Table 6. Comparison by side in females from Sassari†

Traits

d

®®c

®b

®a

n

χ#

(d.f.¯ 1) χ#

!φ

Coronal ossicle 80 3 2 4 89 22±613 0±20 0±587

89±9 3±4 2±2 4±5 0±0001**

Lambdoid ossicle 38 14 13 21 86 10±34 0±04 0±347

44±2 16±3 15±1 24±4 0±0013**

Ossicle at asterion 85 8 3 1 97 0±051 2±27 0±112

87±6 8±2 3±1 1 0±8205

Epipteric bone 71 10 8 5 94 5±697 0±22 0±246

75±5 10±6 8±5 5±3 0±017*

Squamous ossicle 88 2 7 2 99 8±441 2±78 0±292

88±9 2 7±1 2 0±0037**


74±5 13±3 9±2 3±1 0±3855

Frontotemporal articulation 79 0 0 0 79 — — —

100


54±1 16±3 14±3 15±3 0±0056**

Auditory torus 100 0 0 0 100 — — —

100

Palatine torus 57 4 3 34 98 0±14 0±849

58±2 4±1 3±1 34±7Maxillary torus 25 4 2 4 35 7±882 0±67 0±475

71±4 11±4 5±7 11±4 0±005**


98 1 1 — 0±0001**

Supraorbital foramen complete 81 6 10 3 100 3±615 1 0±190

81 6 10 3 0±0572


1984; Brasili-Gualandi & Gualdi-Russo, 1989). This

can obviously be attributed to the common genetic

basis that governs the expression of the traits on the 2

sides of the skull.

The differences between sides sometimes observed

can be explained by the small size of the sample (and

thus to chance factors) or to mechanical factors

(Ossenberg, 1970), physiological factors (Ossenberg,

1969) or to other environmental factors (Berry, 1968;

Trinkaus, 1978).

For bilateral traits, some authors (Korey, 1980;

McGarth et al. 1984; Conner, 1990) have believed

that to avoid an excessive weight in the evaluation of

biological distances, it is best to ‘use the individual as

the unit of study’ or as Konigsberg (1990) stated, to

overcome the problem of the correlation between

sides : ‘ If both sides were observable, one side was

randomly selected (regardless of trait presence or

absence) ; if only one side was observable, it was used

for the scoring’. Scarsini et al. (1980) overcame the

problem by using the average presence and absence of

the traits on the 2 sides according to the mean number

of observable sides.

In our opinion, the problem is not whether to

express the bilateral traits in terms of individuals or of

sides, chosen randomly or not. Each of the methods

has its advantages ; in the one case, underestimating

them in the calculation of biodistances is avoided,

while in the other case information from incomplete

specimens can also be obtained. The main point is not

to lose the information that the symmetry}asymmetry

of expression can provide about exogenous factors

conditioning the expression of the traits. Therefore,

with the aim of losing as little information as possible,

we report the data in the Tables in terms both of

individuals and of sides. In fact, we believe it

preferable also to consider the presence}absence of

symmetry of trait expression; all the more that in our

chosen model of calculation of biological distances

(MMD), there are corrections that take account of the

weight of the bilaterality.

Interpopulation analysis

Taking note of the results of the intrapopulation

analysis, we extended our investigation to 2 other

samples from northern Sardinia : Alghero and Ozieri.

In the Alghero sample (Table 7), the traits with the

highest frequency are the lambdoid ossicle and

parietal foramen absent, followed by palatine torus


Table 7. Presence of the discontinuous traits in Alghero male and female samples (d.f.¯ 1)

Males Females

Traits % % χ# P

Bregmatic bone 2}55 3±6 0}30 0 0±095 0±758

Coronal ossicle 7}59 11±9 3}29 10±3 0±045 0±833

Sagittal ossicle 6}44 13±6 2}26 7±7 0±570 0±450

Lambdoid ossicle 30}55 54±5 18}32 56±2 0±024 0±878

Ossicle at lambda 4}44 9±1 2}27 7±4 0±061 0±805

Ossicle at asterion 8}65 12±3 1}32 3±1 2±148 0±142

Epipteric bone 6}60 10±0 5}29 17±2 0±946 0±331

Squamous ossicle 2}65 3±1 3}32 9±4 1±740 0±187

Parietal notch bone 5}65 7±7 5}32 15±6 1±459 0±227

Frontotemporal articulation 2}65 3±1 2}31 6±5 0±599 0±439

Parietal foramen absent 30}64 46±9 21}32 65±6 3±012 0±083

Auditory torus 1}65 1±5 0}32 0 0±000 1±000

Palatine torus 17}65 26±2 13}30 43±3 2±804 0±094

Maxillary torus 6}32 18±7 2}10 20±0 0±008 0±930

Foramen spinosum open 0}64 0 1}32 3±1 0±126 0±722

Supraorbital foramen complete 14}65 21±5 8}32 25±0 0±147 0±702

Inca bone 0}65 0 0}32 0 — —

Metopism 6}65 9±2 3}32 9±4 0±001 0±982

Table 8. Presence of the discontinuous traits in Ozieri male and female samples (d.f.¯ 1)

Males Females

Traits % % χ# P

Bregmatic bone 1}59 1±7 0}34 0 0±000 1±000

Coronal ossicle 3}59 5±1 4}33 12±1 1±491 0±222

Sagittal ossicle 11}42 26±2 5}33 15±2 1±342 0±247

Lambdoid ossicle 36}53 67±9 20}32 62±5 0±261 0±609

Ossicle at lambda 7}48 14±6 2}32 6±2 1±335 0±248

Ossicle at asterion 9}59 15±3 4}35 11±4 0±270 0±604

Epipteric bone 7}56 12±5 9}34 26±5 2±825 0±093

Squamous ossicle 3}61 4±9 1}35 2±9 0±237 0±627

Parietal notch bone 4}60 6±7 2}35 5±7 0±034 0±854

Frontotemporal articulation 2}62 3±2 0}34 0 0±097 0±756

Parietal foramen absent 37}62 59±7 23}25 65±7 0±346 0±557

Auditory torus 2}62 3±2 0}35 0 0±109 0±742

Palatine torus 23}61 37±7 8}33 24±2 1±756 0±185

Maxillary torus 5}26 19±2 3}16 18±7 0±001 0±969

Foramen spinosum open 3}62 4±8 2}35 5±7 0±035 0±851

Supraorbital foramen complete 17}62 27±4 9}35 25±7 0±033 0±856

Inca bone 1}61 1±6 0}35 0 0±000 1±000

Metopism 7}62 11±3 2}35 5±7 0±826 0±363

and supraorbital foramen complete ; there are no

great differences between the sexes. The Ozieri sample

(Table 8) exhibits a very similar pattern; however,

there are high frequencies also of the epipteric bone in

females and the sagittal ossicle in males.

Comparing these results with those of Sassari, we

note a certain similarity with regard to the most

frequent traits (lambdoid ossicle, parietal foramen

absent and palatine torus), especially in the males.

Some differences are observed in the frequency of the

other traits, for instance the sagittal ossicle, which is

clearly more frequent in the males of Ozieri, the

ossicle at asterion in the Sassari males, etc.

Concerning laterality, we found that symmetry of

expression always prevailed in the Alghero sample.

The statistical tests of symmetry reach significance for

most traits in males (Table 9) (the exceptions are the

coronal, asterion and epipteric ossicles), but only for

some in females (Table 10) (lambdoid and epipteric

ossicles, frontotemporal articulation and palatine


Table 9. Comparison by side in males from Alghero†

Traits

d

®®c

®b

®a

n

χ#

(d.f.¯ 1) χ#

!φ

Coronal ossicle 50 3 2 1 56 0±433 0±20 0±24

89±3 5±4 3±6 1±8 0±5103


49 12±2 12±2 26±5 0±0007**


88±1 8±5 1±7 1±7 0±4802

Epipteric bone 46 4 1 0 63 2±508 1±80 0±04

90±2 7±8 2 0±1133


96±8 1±6 1±6 0±0071**

Parietal notch bone 57 4 0 0 61 — 4 —

93±4 6±6Frontotemporal articulation 62 0 1 0 63 — 1 —

98±4 1±6Parietal foramen absent 34 6 8 16 64 17±75 0±29 0±53

53±1 9±4 12±5 25 0±0001**

Auditory torus 64 1 0 0 65 — 1 —

98±5 1±5Palatine torus 48 1 2 14 65 49±623 0±33 0±87

73±8 1±5 3±1 21±5 0±0001**

Maxillary torus 21 1 0 3 25 17±898 1 0±85

84 4 12 0±0001**

Foramen spinosum open 63 0 0 0 63 — — —

100

Supraorbital foramen complete 51 5 5 4 65 8±199 0 0±36

78±5 7±7 7±7 6±2 0±0042**

† Percentage frequency and probability in italics ; **P! 0±01.

Table 10. Comparison by side in females from Alghero†

Traits

d

®®c

®b

®a

n

χ#

(d.f.¯ 1) χ#

!φ

Coronal ossicle 24 2 1 0 27 2±747 0±33 0±06

88±9 7±4 3±7 0±0975


39±3 10±7 17±9 32±1 0±0219*

Ossicle at asterion 30 1 0 0 31 — 1 —

96±8 3±2Epipteric bone 18 2 0 3 23 7±693 2 0±73

78±3 8±7 13 0±0055**


90±3 3±2 3±2 3±2 0±2696


86±7 6±7 3±3 3±3 0±4642

Frontotemporal articulation 26 1 1 0 28 6±491 0±33 0±04

92±9 3±6 3±6 0±0108*


35±5 12±9 19±4 32±3 0±0945

Auditory torus 32 0 0 0 32 — — —

100

Palatine torus 16 2 2 9 29 14±499 0 0±71

55±2 6±9 6±9 31 0±0001**

Maxillary torus 7 1 1 0 9 1±723 0 0±12

77±8 11±1 11±1 0±1894

Foramen spinosum open 30 1 0 0 31 — 1 —

96±8 3±2Supraorbital foramen complete 24 3 2 3 32 3±799 0±20 0±45

75 9±4 6±2 9±4 0±0513



Table 11. Comparison by side in males from Ozieri†

Traits

d

®®c

®b

®a

n

χ#

(d.f.¯ 1) χ#

!φ

Coronal ossicle 55 2 0 1 58 4±169 2 0±57

94±8 3±4 1±7 0±0412*


32 16 10 42 0±0007**


84±7 1±7 10±2 3±4 0±058

Epipteric bone 41 4 1 2 48 4±114 1±80 0±42

85±4 8±3 2±1 4±2 0±043*

Squamous ossicle 53 0 0 2 55 30±164 — 1

96±4 3±6 0±0001**

Parietal notch bone 54 3 1 0 58 4±169 1 0±03

93±1 5±2 1±7 0±0412*

Frontotemporal articulation 60 0 0 2 62 34±104 — 1

96±8 3±2 0±001**


40±3 17±7 16±1 25±8 0±0152*

Auditory torus 60 1 0 1 62 7±123 1 0±70

96±8 1±6 1±6 0±0076**

Palatine torus 38 3 2 18 61 40±71 2 0±82

62±3 4±9 3±3 29±5 0±0001**

Maxillary torus 19 0 1 3 23 10±442 1 0±84

82±6 4±3 13 0±0012**

Foramen spinosum open 55 0 3 0 58 — 3 —

94±8 5±2Supraorbital foramen complete 45 7 6 4 62 4±047 0±08 0±26

72±6 11±3 9±7 6±5 0±0442*


Table 12. Comparison by side in females from Ozieri†

Traits

d

®®c

®b

®a

n

χ#

(d.f.¯ 1) χ#

!φ

Coronal ossicle 28 3 0 1 32 1±327 3 0±48

87±5 9±4 3±1 0±2493


36±7 13±3 43±3 6±7 0±0009**


88±2 2±9 5±9 2±9 0±2212

Epipteric bone 25 3 2 3 33 6±927 0±2 0±46

75±8 9±1 6±1 9±1 0±0085**

Squamous ossicle 33 1 0 0 34 — 1 —

97±1 2±9Parietal notch bone 32 1 1 0 34 7±993 0 0±03

94±1 2±9 2±9 0±0047**

Frontotemporal articulation 32 0 0 0 32 — — —

100

Parietal foramen absent 12 4 8 11 35 3±838 1 0±33

34±3 11±4 22±9 31±4 0±0501

Auditory torus 35 0 0 0 35 — — —

100

Palatine torus 25 0 1 7 33 22±776 1 0±92

75±8 3 21±2 0±0001**

Maxillary torus 12 0 1 1 14 1±122 1 0±68

85±7 7±1 7±1 0±2895


93±7 3±1 3±1 0±0663

Supraorbital foramen complete 26 4 4 1 35 0±087 — 0±07

74±3 11±4 11±4 2±9 0±7674

† Percentage frequency and probability in italics ; **P! 0±01.


FEMALES

MALES

0.0000.0040.0080.0120.016

0.04 0.03 0.02 0.01 –0.00

SASSARI

ALGHERO

OZIERI

SASSARI

ALGHERO

OZIERI

Fig. Biological distances for female and male Sardinian series.

torus). In the Ozieri males (Table 11), symmetric trait

expression is always significantly more frequent, while

the females (Table 12) show this condition only for the

lambdoid and epipteric ossicles, the parietal notch

bone and the palatine torus.

On the basis of the frequencies of the 18 nonmetric

traits, we calculated the biological distances among

the 3 Sardinian series (Fig.). The greatest distance was

between the males of Sassari and Ozieri, which reaches

the limits of statistical significance, and between the

females of Ozieri and Alghero.

In view of the biological and cultural peculiarities

of the Sardinian populations, it seemed interesting at

this point to compare the results based on nonmetric

traits with those based on blood genetic markers.

However, despite the large number of relevant studies

(Pettener et al. 1990; Gruppioni et al. 1991; Brasili-

Gualandi et al. 1993; Vona, 1997), there are not many

possible comparisons, since the various authors

usually refer to the subdivision of the territory into

historical-geographical areas and not to single places,

as in our case. The latter are instead considered in

Martuzzi-Veronesi et al. (1983), in which the values of

genetic distance (Cavalli Sforza & Edwards, 1967,

Cavalli Sforza et al. 1969) (Alghero}Ozieri¯0±03772, Alghero}Sassari¯0±02084, Ozieri}Sassari¯0±03198) and kinship (Morton, 1973) (Alghero}Ozieri¯®0±00012, Alghero}Sassari¯ 0±00046,

Ozieri}Sassari¯®0±00083) calculated on the basis

of the ABO, Rh and Kell systems exhibit distances

between the considered areas that are similar to those

found by us on the basis of nonmetric traits. Our

results agree with the subdivision into historical-

geographical areas proposed by Carta Raspi (1971),

which stated that Alghero and Sassari are included

in Nurra, while Ozieri is part of Logudoro.

The first aim of the present study was to broaden our

knowledge of the importance of sex, age and laterality

in the analysis of nonmetric traits as indicators of the

biological distance between populations.

Our results for the sample of Sassari, supported

also by those of Ozieri and Alghero and by literature

reports, suggest that it is not possible at present to

assume a definitive position on the influence of sex on

the expression of nonmetric traits. In fact, there are

significant differences both in our results and in those

reported by other authors, but the traits involved vary

according to the population studied. This aspect is in

contrast with the choice of traits with a strong genetic

component, which should behave, even if dependent

on the sex, in a similar manner in the different

populations. However, since we do not have a clear

indication of the role played by sex, we believe that it

is preferable, where possible, to take sex differences

into account, even though the contrary situation

should not invalidate the results obtained from

calculation of the biodistance on account of the

genetic basis of the considered traits.

The age of the individual does not appear to affect

the expression of the nonmetric traits. However, for

these samples, as for the previous ones examined


(Siena, Bologna), we observed that advanced age

reduces the ‘ legibility ’ of some traits and thus can

limit their use as indicators, especially in cases where

populations are studied that include a high percentage

of elderly individuals.

It appears to be important to consider the laterality

of discontinuous traits, especially to avoid losing

information about the influence of the environment,

which might be the basis of possible asymmetries. On

the other hand, use of the MMD as the coefficient of

distance avoids some problems in this respect, since it

allows contemporaneously the sides and their cor-

relation to be considered.

The results of our interpopulation analysis, con-

cerning the variability of the Sardinian populations,

are encouraging. In particular, the agreement between

our results and those from the same populations

obtained with blood genetic markers is interesting.

This trend strengthens the hypothesis of the validity of

the use of nonmetric traits in the study of the peopling

of a territory. The results of the present investigation

prompt us to extend our study to other samples of

Sardinia for a broader and more complete evaluation

of the relationships among the populations of the

different regions of the island.

The current study was supported by CNR grant N.

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